javax.servlet.http
Interface HttpServletResponse

public abstract interface HttpServletResponse
extends ServletResponse

Defines an HTTP servlet response that a servlet running on a Web server sends to a client using HTTP. This interface allows the servlet's service method to access HTTP headers and return data to its client. The servlet engine implements this interface.

Version:
$Version$
Author:
Various
See Also:
ServletResponse

Field Summary
static int SC_ACCEPTED
          Status code (202) indicating that a request was accepted for processing, but was not completed.
static int SC_BAD_GATEWAY
          Status code (502) indicating that the HTTP server received an invalid response from a server it consulted when acting as a proxy or gateway.
static int SC_BAD_REQUEST
          Status code (400) indicating the request sent by the client was syntactically incorrect.
static int SC_CONFLICT
          Status code (409) indicating that the request could not be completed due to a conflict with the current state of the resource.
static int SC_CONTINUE
          Status code (100) indicating the client can continue.
static int SC_CREATED
          Status code (201) indicating the request succeeded and created a new resource on the server.
static int SC_FORBIDDEN
          Status code (403) indicating the server understood the request but refused to fulfill it.
static int SC_GATEWAY_TIMEOUT
          Status code (504) indicating that the server did not receive a timely response from the upstream server while acting as a gateway or proxy.
static int SC_GONE
          Status code (410) indicating that the resource is no longer available at the server and no forwarding address is known.
static int SC_HTTP_VERSION_NOT_SUPPORTED
          Status code (505) indicating that the server does not support or refuses to support the HTTP protocol version that was used in the request message.
static int SC_INTERNAL_SERVER_ERROR
          Status code (500) indicating an error inside the HTTP server which prevented it from fulfilling the request.
static int SC_LENGTH_REQUIRED
          Status code (411) indicating that the request cannot be handled without a defined Content-Length.
static int SC_METHOD_NOT_ALLOWED
          Status code (405) indicating that the method specified in the Request-Line is not allowed for the resource identified by the Request-URI.
static int SC_MOVED_PERMANENTLY
          Status code (301) indicating that the resource has permanently moved to a new location, and that future references should use a new URI with their requests.
static int SC_MOVED_TEMPORARILY
          Status code (302) indicating that the resource has temporarily moved to another location, but that future references should still use the original URI to access the resource.
static int SC_MULTIPLE_CHOICES
          Status code (300) indicating that the requested resource corresponds to any one of a set of representations, each with its own specific location.
static int SC_NO_CONTENT
          Status code (204) indicating that the request succeeded but that there was no new information to return.
static int SC_NON_AUTHORITATIVE_INFORMATION
          Status code (203) indicating that the meta information presented by the client did not originate from the server.
static int SC_NOT_ACCEPTABLE
          Status code (406) indicating that the resource identified by the request is only capable of generating response entities which have content characteristics not acceptable according to the accept headerssent in the request.
static int SC_NOT_FOUND
          Status code (404) indicating that the requested resource is not available.
static int SC_NOT_IMPLEMENTED
          Status code (501) indicating the HTTP server does not support the functionality needed to fulfill the request.
static int SC_NOT_MODIFIED
          Status code (304) indicating that a conditional GET operation found that the resource was available and not modified.
static int SC_OK
          Status code (200) indicating the request succeeded normally.
static int SC_PARTIAL_CONTENT
          Status code (206) indicating that the server has fulfilled the partial GET request for the resource.
static int SC_PAYMENT_REQUIRED
          Status code (402) reserved for future use.
static int SC_PRECONDITION_FAILED
          Status code (412) indicating that the precondition given in one or more of the request-header fields evaluated to false when it was tested on the server.
static int SC_PROXY_AUTHENTICATION_REQUIRED
          Status code (407) indicating that the client MUST first authenticate itself with the proxy.
static int SC_REQUEST_ENTITY_TOO_LARGE
          Status code (413) indicating that the server is refusing to process the request because the request entity is larger than the server is willing or able to process.
static int SC_REQUEST_TIMEOUT
          Status code (408) indicating that the client did not produce a requestwithin the time that the server was prepared to wait.
static int SC_REQUEST_URI_TOO_LONG
          Status code (414) indicating that the server is refusing to service the request because the Request-URI is longer than the server is willing to interpret.
static int SC_RESET_CONTENT
          Status code (205) indicating that the agent SHOULD reset the document view which caused the request to be sent.
static int SC_SEE_OTHER
          Status code (303) indicating that the response to the request can be found under a different URI.
static int SC_SERVICE_UNAVAILABLE
          Status code (503) indicating that the HTTP server is temporarily overloaded, and unable to handle the request.
static int SC_SWITCHING_PROTOCOLS
          Status code (101) indicating the server is switching protocols according to Upgrade header.
static int SC_UNAUTHORIZED
          Status code (401) indicating that the request requires HTTP authentication.
static int SC_UNSUPPORTED_MEDIA_TYPE
          Status code (415) indicating that the server is refusing to service the request because the entity of the request is in a format not supported by the requested resource for the requested method.
static int SC_USE_PROXY
          Status code (305) indicating that the requested resource MUST be accessed through the proxy given by the Location field.
 
Method Summary
 void addCookie(Cookie cookie)
          Adds the specified cookie to the response.
 boolean containsHeader(java.lang.String name)
          Checks whether the response message header has a field with the specified name.
 java.lang.String encodeRedirectUrl(java.lang.String url)
          Deprecated. Use encodeRedirectURL(String url)
 java.lang.String encodeRedirectURL(java.lang.String url)
          Encodes the specified URL for use in the sendRedirect method or, if encoding is not needed, returns the URL unchanged.
 java.lang.String encodeUrl(java.lang.String url)
          Deprecated. Use encodeURL(String url)
 java.lang.String encodeURL(java.lang.String url)
          Encodes the specified URL by including the session ID in it, or, if encoding is not needed, returns the URL unchanged.
 void sendError(int sc)
          Sends an error response to the client using the specified status code and a default message.
 void sendError(int sc, java.lang.String msg)
          Sends an error response to the client using the specified status code and descriptive message.
 void sendRedirect(java.lang.String location)
          Sends a temporary redirect response to the client using the specified redirect location URL.
 void setDateHeader(java.lang.String name, long date)
          Adds a field to the response header with the given name and date-valued field.
 void setHeader(java.lang.String name, java.lang.String value)
          Adds a field to the response header with the given name and value.
 void setIntHeader(java.lang.String name, int value)
          Adds a field to the response header with the given name and integer value.
 void setStatus(int sc)
          Sets the status code for this response.
 void setStatus(int sc, java.lang.String sm)
          Deprecated. ambiguous meaning. To send an error with a description page, use sendError(int sc, String msg);
 
Methods inherited from interface javax.servlet.ServletResponse
getCharacterEncoding, getOutputStream, getWriter, setContentLength, setContentType
 

Field Detail

SC_CONTINUE

public static final int SC_CONTINUE
Status code (100) indicating the client can continue.

SC_SWITCHING_PROTOCOLS

public static final int SC_SWITCHING_PROTOCOLS
Status code (101) indicating the server is switching protocols according to Upgrade header.

SC_OK

public static final int SC_OK
Status code (200) indicating the request succeeded normally.

SC_CREATED

public static final int SC_CREATED
Status code (201) indicating the request succeeded and created a new resource on the server.

SC_ACCEPTED

public static final int SC_ACCEPTED
Status code (202) indicating that a request was accepted for processing, but was not completed.

SC_NON_AUTHORITATIVE_INFORMATION

public static final int SC_NON_AUTHORITATIVE_INFORMATION
Status code (203) indicating that the meta information presented by the client did not originate from the server.

SC_NO_CONTENT

public static final int SC_NO_CONTENT
Status code (204) indicating that the request succeeded but that there was no new information to return.

SC_RESET_CONTENT

public static final int SC_RESET_CONTENT
Status code (205) indicating that the agent SHOULD reset the document view which caused the request to be sent.

SC_PARTIAL_CONTENT

public static final int SC_PARTIAL_CONTENT
Status code (206) indicating that the server has fulfilled the partial GET request for the resource.

SC_MULTIPLE_CHOICES

public static final int SC_MULTIPLE_CHOICES
Status code (300) indicating that the requested resource corresponds to any one of a set of representations, each with its own specific location.

SC_MOVED_PERMANENTLY

public static final int SC_MOVED_PERMANENTLY
Status code (301) indicating that the resource has permanently moved to a new location, and that future references should use a new URI with their requests.

SC_MOVED_TEMPORARILY

public static final int SC_MOVED_TEMPORARILY
Status code (302) indicating that the resource has temporarily moved to another location, but that future references should still use the original URI to access the resource.

SC_SEE_OTHER

public static final int SC_SEE_OTHER
Status code (303) indicating that the response to the request can be found under a different URI.

SC_NOT_MODIFIED

public static final int SC_NOT_MODIFIED
Status code (304) indicating that a conditional GET operation found that the resource was available and not modified.

SC_USE_PROXY

public static final int SC_USE_PROXY
Status code (305) indicating that the requested resource MUST be accessed through the proxy given by the Location field.

SC_BAD_REQUEST

public static final int SC_BAD_REQUEST
Status code (400) indicating the request sent by the client was syntactically incorrect.

SC_UNAUTHORIZED

public static final int SC_UNAUTHORIZED
Status code (401) indicating that the request requires HTTP authentication.

SC_PAYMENT_REQUIRED

public static final int SC_PAYMENT_REQUIRED
Status code (402) reserved for future use.

SC_FORBIDDEN

public static final int SC_FORBIDDEN
Status code (403) indicating the server understood the request but refused to fulfill it.

SC_NOT_FOUND

public static final int SC_NOT_FOUND
Status code (404) indicating that the requested resource is not available.

SC_METHOD_NOT_ALLOWED

public static final int SC_METHOD_NOT_ALLOWED
Status code (405) indicating that the method specified in the Request-Line is not allowed for the resource identified by the Request-URI.

SC_NOT_ACCEPTABLE

public static final int SC_NOT_ACCEPTABLE
Status code (406) indicating that the resource identified by the request is only capable of generating response entities which have content characteristics not acceptable according to the accept headerssent in the request.

SC_PROXY_AUTHENTICATION_REQUIRED

public static final int SC_PROXY_AUTHENTICATION_REQUIRED
Status code (407) indicating that the client MUST first authenticate itself with the proxy.

SC_REQUEST_TIMEOUT

public static final int SC_REQUEST_TIMEOUT
Status code (408) indicating that the client did not produce a requestwithin the time that the server was prepared to wait.

SC_CONFLICT

public static final int SC_CONFLICT
Status code (409) indicating that the request could not be completed due to a conflict with the current state of the resource.

SC_GONE

public static final int SC_GONE
Status code (410) indicating that the resource is no longer available at the server and no forwarding address is known. This condition SHOULD be considered permanent.

SC_LENGTH_REQUIRED

public static final int SC_LENGTH_REQUIRED
Status code (411) indicating that the request cannot be handled without a defined Content-Length.

SC_PRECONDITION_FAILED

public static final int SC_PRECONDITION_FAILED
Status code (412) indicating that the precondition given in one or more of the request-header fields evaluated to false when it was tested on the server.

SC_REQUEST_ENTITY_TOO_LARGE

public static final int SC_REQUEST_ENTITY_TOO_LARGE
Status code (413) indicating that the server is refusing to process the request because the request entity is larger than the server is willing or able to process.

SC_REQUEST_URI_TOO_LONG

public static final int SC_REQUEST_URI_TOO_LONG
Status code (414) indicating that the server is refusing to service the request because the Request-URI is longer than the server is willing to interpret.

SC_UNSUPPORTED_MEDIA_TYPE

public static final int SC_UNSUPPORTED_MEDIA_TYPE
Status code (415) indicating that the server is refusing to service the request because the entity of the request is in a format not supported by the requested resource for the requested method.

SC_INTERNAL_SERVER_ERROR

public static final int SC_INTERNAL_SERVER_ERROR
Status code (500) indicating an error inside the HTTP server which prevented it from fulfilling the request.

SC_NOT_IMPLEMENTED

public static final int SC_NOT_IMPLEMENTED
Status code (501) indicating the HTTP server does not support the functionality needed to fulfill the request.

SC_BAD_GATEWAY

public static final int SC_BAD_GATEWAY
Status code (502) indicating that the HTTP server received an invalid response from a server it consulted when acting as a proxy or gateway.

SC_SERVICE_UNAVAILABLE

public static final int SC_SERVICE_UNAVAILABLE
Status code (503) indicating that the HTTP server is temporarily overloaded, and unable to handle the request.

SC_GATEWAY_TIMEOUT

public static final int SC_GATEWAY_TIMEOUT
Status code (504) indicating that the server did not receive a timely response from the upstream server while acting as a gateway or proxy.

SC_HTTP_VERSION_NOT_SUPPORTED

public static final int SC_HTTP_VERSION_NOT_SUPPORTED
Status code (505) indicating that the server does not support or refuses to support the HTTP protocol version that was used in the request message.
Method Detail

addCookie

public void addCookie(Cookie cookie)
Adds the specified cookie to the response. It can be called multiple times to set more than one cookie.
Parameters:
cookie - the Cookie to return to the client

containsHeader

public boolean containsHeader(java.lang.String name)
Checks whether the response message header has a field with the specified name.
Parameters:
name - the header field name
Returns:
true if the response message header has a field with the specified name; false otherwise

encodeURL

public java.lang.String encodeURL(java.lang.String url)
Encodes the specified URL by including the session ID in it, or, if encoding is not needed, returns the URL unchanged. The implementation of this method should include the logic to determine whether the session ID needs to be encoded in the URL. For example, if the browser supports cookies, or session tracking is turned off, URL encoding is unnecessary.

All URLs emitted by a Servlet should be run through this method. Otherwise, URL rewriting cannot be used with browsers which do not support cookies.

Parameters:
url - the url to be encoded.
Returns:
the encoded URL if encoding is needed; the unchanged URL otherwise.

encodeRedirectURL

public java.lang.String encodeRedirectURL(java.lang.String url)
Encodes the specified URL for use in the sendRedirect method or, if encoding is not needed, returns the URL unchanged. The implementation of this method should include the logic to determine whether the session ID needs to be encoded in the URL. Because the rules for making this determination differ from those used to decide whether to encode a normal link, this method is seperate from the encodeUrl method.

All URLs sent to the HttpServletResponse.sendRedirect method should be run through this method. Otherwise, URL rewriting canont be used with browsers which do not support cookies.

After this method is called, the response should be considered to be committed and should not be written to.

Parameters:
url - the url to be encoded.
Returns:
the encoded URL if encoding is needed; the unchanged URL otherwise.
See Also:
sendRedirect(java.lang.String), encodeUrl(java.lang.String)

encodeUrl

public java.lang.String encodeUrl(java.lang.String url)
Deprecated. Use encodeURL(String url)
Encodes the specified URL by including the session ID in it, or, if encoding is not needed, returns the URL unchanged. The implementation of this method should include the logic to determine whether the session ID needs to be encoded in the URL. For example, if the browser supports cookies, or session tracking is turned off, URL encoding is unnecessary.

All URLs emitted by a Servlet should be run through this method. Otherwise, URL rewriting cannot be used with browsers which do not support cookies.

Parameters:
url - the url to be encoded.
Returns:
the encoded URL if encoding is needed; the unchanged URL otherwise.

encodeRedirectUrl

public java.lang.String encodeRedirectUrl(java.lang.String url)
Deprecated. Use encodeRedirectURL(String url)
Encodes the specified URL for use in the sendRedirect method or, if encoding is not needed, returns the URL unchanged. The implementation of this method should include the logic to determine whether the session ID needs to be encoded in the URL. Because the rules for making this determination differ from those used to decide whether to encode a normal link, this method is seperate from the encodeUrl method.

All URLs sent to the HttpServletResponse.sendRedirect method should be run through this method. Otherwise, URL rewriting canont be used with browsers which do not support cookies.

Parameters:
url - the url to be encoded.
Returns:
the encoded URL if encoding is needed; the unchanged URL otherwise.

sendError

public void sendError(int sc,
                      java.lang.String msg)
               throws java.io.IOException
Sends an error response to the client using the specified status code and descriptive message. If setStatus has previously been called, it is reset to the error status code. The message is sent as the body of an HTML page, which is returned to the user to describe the problem. The page is sent with a default HTML header; the message is enclosed in simple body tags (<body></body>).

After using this method, the response should be considered to be committed and should not be written to.

Parameters:
sc - the status code
msg - the detail message
Throws:
java.io.IOException - If an I/O error has occurred.

sendError

public void sendError(int sc)
               throws java.io.IOException
Sends an error response to the client using the specified status code and a default message.
Parameters:
sc - the status code
Throws:
java.io.IOException - If an I/O error has occurred.

sendRedirect

public void sendRedirect(java.lang.String location)
                  throws java.io.IOException
Sends a temporary redirect response to the client using the specified redirect location URL. The URL must be absolute (for example, https://hostname/path/file.html). Relative URLs are not permitted here.
Parameters:
location - the redirect location URL
Throws:
java.io.IOException - If an I/O error has occurred.

setDateHeader

public void setDateHeader(java.lang.String name,
                          long date)
Adds a field to the response header with the given name and date-valued field. The date is specified in terms of milliseconds since the epoch. If the date field had already been set, the new value overwrites the previous one. The containsHeader method can be used to test for the presence of a header before setting its value.
Parameters:
name - the name of the header field
value - the header field's date value
See Also:
containsHeader(java.lang.String)

setHeader

public void setHeader(java.lang.String name,
                      java.lang.String value)
Adds a field to the response header with the given name and value. If the field had already been set, the new value overwrites the previous one. The containsHeader method can be used to test for the presence of a header before setting its value.
Parameters:
name - the name of the header field
value - the header field's value
See Also:
containsHeader(java.lang.String)

setIntHeader

public void setIntHeader(java.lang.String name,
                         int value)
Adds a field to the response header with the given name and integer value. If the field had already been set, the new value overwrites the previous one. The containsHeader method can be used to test for the presence of a header before setting its value.
Parameters:
name - the name of the header field
value - the header field's integer value
See Also:
containsHeader(java.lang.String)

setStatus

public void setStatus(int sc)
Sets the status code for this response. This method is used to set the return status code when there is no error (for example, for the status codes SC_OK or SC_MOVED_TEMPORARILY). If there is an error, the sendError method should be used instead.
Parameters:
sc - the status code
See Also:
sendError(int, java.lang.String)

setStatus

public void setStatus(int sc,
                      java.lang.String sm)
Deprecated. ambiguous meaning. To send an error with a description page, use sendError(int sc, String msg);
Sets the status code and message for this response. If the field had already been set, the new value overwrites the previous one. The message is sent as the body of an HTML page, which is returned to the user to describe the problem. The page is sent with a default HTML header; the message is enclosed in simple body tags (<body></body>).
Parameters:
sc - the status code
sm - the status message